You may get this warning just for using a selector in your own code or third party code that has the same name as some selector that is marked as non-public. Happens to me all the time. Never got rejected for it.
By “same name” i mean just something as simple as you having an object with this selector:
-(id) XYZKMyClass doSomethingFancy:(id) toThis
…and there being a selector like this for an internal Apple functionality
-(id) ApplesClass doSomethingFancy:(id) toSomething
So: What it seems they are looking for is the signature -(id) doSomethingFancy:(id). You can see how it’s very easy to accidentally bump up against this.
Presumably they perform a deeper check at the App Store Police HQ, and determine that the flagged selector is in your code, and hence OK.